Oxfam revealed today that Britain's five richest families were wealthier than the poorest 20% of the population.

Boasting a combined fortune of £28.2 billion, we take a look at the UK's wealthiest billionaire families and where they derive their riches from.

Gerald Cavendish Grosvenor and family

The 6th Duke of Westminster Gerald Grosvenor is the UK's richest landlord. The 62-year-old is worth around £7.9 billion, owning 190 acres in Belgravia, an area adjacent to Buckingham Palace and one of London's most expensive boroughs. The Grosvenor family also own 96,000 acres in Scotland, 32,000 acres in Spain and thousands elsewhere in England. Gerald Grosvenor is a father of four children and his only son, 22-year-old Hugh Grosvenor, is Prince George's youngest godfather. The Grosvenor family are the 81st richest in the world according to the Forbes rich list.

David and Simon Reuben

The Reuben brothers are property tycoons with an estimated £6.9 billion fortune, making them the second richest family in Britain. Although owning a vast property empire which includes Millbank Tower and Carlton House on St James's square, Simon Reuben started out importing carpets and buying real estate, while older brother David was in metals trading. The pair sold their metals trading company TransWorld to Russians Sibneft in the late 90s and now boast an impressive real estate portfolio. Their Reuben Foundation funds health care and educational causes.

The Hinduja brothers

Srichand and Gopichand Hinduja, co-chairs of their global conglomerate Hinduja Group, are worth an estimated £6 billion. Their multinational company has a presence in 37 countries and is involved in all things from trucks and lubricants to banking and healthcare. The family's assets include the 67,000 square foot Carlton House Terrace, a heritage mansion in London on the site of a former palace near Buckingham Palace valued at an estimated 500 million US dollars (£300 million). The Hinduja's are India's sixth richest family according to Forbes and 122nd richest billionaires in the world.

Charles Cadogan and family

The 8th Earl of Cadogan, a former chairman of Chelsea Football Club, is estimated to be worth £4 billion. The Earl's 300-year-old property portfolio, Cadogan Estates, is known for its redevelopment of Sloane Street in west London and ownership of a 90-acre estate that stretches across the boroughs of Chelsea and Knightsbridge. The Eton-educated Earl inherited his title after the death of his father in 1997 and began his career as a merchant banker at Schroder Wagg.

Mike Ashley

Newcastle United owner Mike Ashley is Britain's fifth richest man with an estimated £3.3 billion fortune. Mr Ashley founded his Sports Direct clothing company after leaving school in 1982, and is one of the country's most reclusive billionaires despite his ownership of the premiership club in 2007. The 49-year-old was the sole owner of the company before it went public in 2007, but remains as the deputy executive chairman of Sports Direct which owns brands including Dunlop, Karrimor and Slazenger.